645168444 has 24 divisors (see below), whose sum is σ = 1507161600. Its totient is φ = 214803504.

The previous prime is 645168443. The next prime is 645168451. The reversal of 645168444 is 444861546.

It is a happy number.

It is a super-2 number, since 2×645168444² = 832484642266762272, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 645168396 and 645168405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645168443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20794 + ... + 41505.

It is an arithmetic number, because the mean of its divisors is an integer number (62798400).

Almost surely, 2^645168444 is an apocalyptic number.

It is an amenable number.

645168444 is an abundant number, since it is smaller than the sum of its proper divisors (861993156).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645168444 is a wasteful number, since it uses less digits than its factorization.

645168444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63169 (or 63167 counting only the distinct ones).

The product of its digits is 368640, while the sum is 42.

The square root of 645168444 is about 25400.1662199286. The cubic root of 645168444 is about 864.0874664966.

The spelling of 645168444 in words is "six hundred forty-five million, one hundred sixty-eight thousand, four hundred forty-four".